Substantia Nigra Pathology Predicts Disability in Multiple Sclerosis

Rohit Bakshi, MD, FAAN reviewing Walter U et al. Neurology 2009 Sep 29

Serial transcranial neurosonology in patients with MS reveals a possible link between substantia nigra pathology and progression of neurological disability.

Multiple sclerosis (MS) is known to affect the basal ganglia and other gray-matter regions (Neurology 2007; 68:634). Involvement of gray matter correlates with numerous clinical manifestations of the disease, such as fatigue, physical disability, and cognitive impairment. Now, researchers have used transcranial neurosonology, a novel imaging approach, to assess the basal ganglia in 75 patients with MS and in 55 healthy controls.

Compared with the controls, the patients with MS were more likely to show hyperechogenicity in the substantia nigra, lentiform nucleus, caudate nucleus, and thalamus. The size of echogenic area in some of the gray-matter structures correlated with hypointensity on T2-weighted magnetic resonance images (MRIs), suggesting that iron deposition was responsible for the hyperechogenicity. The degree of substantia nigra changes at baseline predicted the 2-year risk for progression of neurological disability. However, hyperechogenicity of the gray-matter structures did not differ among MS clinical phenotype groups, such as relapsing-remitting and secondary-progressive MS. Furthermore, the gray-matter changes showed only weak to moderate correlations with disability level.

Comment

The advantages of neurosonology include relatively low cost and ease of use compared with MRI or functional imaging techniques. The authors applied neurosonology in a unique way to study tissue changes in MS. The findings confirm previous data indicating that iron-related changes in gray matter are linked to disability in MS (JW Neurol Apr 28 2009; Neurotherapeutics 2007; 4:371; and Ann N Y Acad Sci 2004; 1012:252). To determine what role, if any, this technique will play in MS imaging, future studies should compare the sensitivity and validity of transcranial neurosonology in predicting MS progression with the sensitivity and validity of established MRI-based methods of tracking iron deposition.

https://www.jwatch.org/jn201009140000001/2010/09/14/substantia-nigra-pathology-predicts-disability

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